Quote Originally Posted by TopJimmyCooks View Post
Mintemp- as a safety measure, the Marlin firmware shuts down the printer if the hotend thermistor reads Zero (0) degrees. It assumes the thermistor has failed and shuts the power down, to avoid a runaway heating issue.

Your thermistor is not working right, and since it's reading zero its probably not wired/connected right. when you turn the printer on and poll the temperature in pronterface, it should show room temperature for both bed and hotend, 18 to 24 degrees or so.
I'm getting temperature readings on ex0 and bed. Apparently pronterface is trying to get a temperature reading for ex1(which I don't have a second extruder) when I connect the thermistor from the bed to the ex1 slot the error goes away.

So my question is how do I set pronterface or firmware to only work with ex0?